Problem: Reduce to lowest terms: $- \dfrac{5}{3} \div - \dfrac{7}{8} = {?}$
Dividing by a fraction is the same as multiplying by the reciprocal of the fraction. The reciprocal of $- \dfrac{7}{8}$ is $- \dfrac{8}{7}$ Therefore: $ - \dfrac{5}{3} \div - \dfrac{7}{8} = - \dfrac{5}{3} \times - \dfrac{8}{7} $ $ \phantom{- \dfrac{5}{3} \times - \dfrac{8}{7}} = \dfrac{-5 \times -8}{3 \times 7} $ $ \phantom{- \dfrac{5}{3} \times - \dfrac{8}{7}} = \dfrac{40}{21} $